What antibiotics are recommended for treating an upper respiratory infection (URI)?

Antibiotics for Upper Respiratory Infections

Most upper respiratory infections (URIs) are viral in origin and do not require antibiotics. Inappropriate antibiotic use contributes to antibiotic resistance, adverse events, and unnecessary costs 1.

When to Consider Antibiotics

Antibiotics should be considered only in specific circumstances:

• Bacterial sinusitis: When symptoms persist beyond 7-10 days, worsen after initial improvement, or are severe (high fever, purulent discharge, facial pain) 2
• Streptococcal pharyngitis: Confirmed by rapid testing or culture 2
• Bacterial otitis media: With severe symptoms or high-risk factors 2
• Persistent symptoms: When initial symptomatic treatment fails 2

First-Line Antibiotic Options

When antibiotics are clinically indicated:

1. Amoxicillin:

   • First choice for suspected pneumococcal infections 3
   • Adults: 3g/day divided into 3 doses 2
   • Children: 80-100mg/kg/day in three daily doses for those <30kg 2
   • Duration: 5-8 days for most URIs 4

2. Amoxicillin-clavulanate:

   • Preferred when beta-lactamase-producing pathogens are suspected 2, 4
   • Provides coverage against H. influenzae and M. catarrhalis 5
   • Higher risk of adverse events compared to amoxicillin alone 2

3. Macrolides (e.g., azithromycin, clarithromycin):

   • Alternative for patients with penicillin allergy 4
   • Not recommended as first-line due to increasing pneumococcal resistance 2
   • Azithromycin: 500mg daily for 3 days 6
   • Clarithromycin: 250mg twice daily for 10 days 6

Second-Line Options

For treatment failures or specific situations:

1. Cephalosporins:

   • Second generation (cefuroxime-axetil): Effective in 5 days 2
   • Third generation (cefpodoxime-proxetil): Alternative to amoxicillin-clavulanate 2

2. Doxycycline:

   • Alternative for penicillin-allergic patients 7
   • Effective against respiratory pathogens including atypical organisms 7

3. Respiratory fluoroquinolones (levofloxacin, moxifloxacin):

   • Reserved for treatment failures or high-risk situations 2
   • Should not be used as first-line therapy 4

Special Considerations

• Treatment duration: Generally 5-8 days for most URIs; reassess after 48-72 hours 2, 4
• Beta-lactam allergies: Consider macrolides, doxycycline, or pristinamycin 2, 7
• Children under 3 years: Amoxicillin is preferred; avoid macrolides and tetracyclines 2
• Sinusitis location: Treatment varies based on sinus involvement (maxillary, frontal, ethmoidal, sphenoidal) 2

Common Pitfalls to Avoid

1. Overprescribing antibiotics for viral URIs, which represent the majority of cases
2. Using broad-spectrum antibiotics when narrow-spectrum would suffice
3. Inadequate dosing or duration leading to treatment failure
4. Not considering local resistance patterns when selecting antibiotics
5. Failing to reassess after 48-72 hours of treatment

Remember that most URIs are self-limiting viral infections that will resolve without antibiotics. When antibiotics are indicated, amoxicillin or amoxicillin-clavulanate are typically the most appropriate first-line choices based on clinical presentation and local resistance patterns.